KUALA LUMPUR, Malaysia - Doctors Without Borders says rising intellectual property rights are blocking the generic production of newer drugs to treat HIV and keeping them out of reach for developing countries.

The medical aid group says prices of older drugs have generally fallen as India and other countries make generics. But newer drugs that are more effective against the AIDS virus are too expensive, costing up to 15 times more.

Patients are treated with a combination of three or four drugs, but those who developed resistance to these drugs will need the newer medicines.

The group on Tuesday urged the U.S. and 11 other countries not to sign a Trans-Pacific Partnership they are negotiating. The group says the pact will increase intellectual property rights in the Asia-Pacific region and risk access to medicines.